Nivo Slider doesn't show images

Hello,

I installed Nivo Slider and configured it correctly but it does not show up well.
When the page is loading I see some of the pictures but when Nivo Slider is ready they are overlapped and the CSS-properties don't change. When I use Firebug to change the display-property of one image from hidden to eg. block the picture is visible.

I use the latest version of Nivo Slider and jQuery 1.3.2. The site I want to use the Slider is http://www.furtgo.at/neue-startseite

Is someone able to help me, please?